1. Field of the Invention
This invention relates to an extendible and tractable linear stabilizer which is readily attached to and detached from the frame of a work vehicle. Usually such stabilizers operate in pairs, and when the stabilizers are extended more down pressure can be exerted on a ground engaging implement carried by the vehicle and the stabilizers act as a brake holding the work vehicle in position during operation of the implement.
2. Description of the Prior Art:
U.S. Pat. No. 3,630,317 Jacobsson shows two hydraulically operated stabilizers on a three-wheel fork truck which stabilizers are automatically actuated when the load carriage of the vehicle is raised.
U.S. Pat. No. 4,018,458 Shumaker shows a stabilizer for a vehicle which consists of a pair of telescopic members with one member being mounted on the vehicle and the other member having a ground engaging foot supported on the free end thereof for rotation in a horizontal plane. The stabilizer incorporates latch means between the telescopic member and the foot for holding the foot in a plurality of rotated positions with respect to the telescopic member, whereby the angular position of maximum stability for the vehicle can be varied.
U.S. Pat. No. 4,082,197 Stedman shows an articulated vehicle having rear and front frames pivotally connected together and a pair of steering cylinders pivotally connected between the rear and front frames for pivoting them relative to each other. A telescopic boom is pivotally mounted on the rear frame and has a work implement, such as a fork, attached to the end of the boom. A pair of lift cylinders are pivotally connected to opposite sides of the front frame and to a ground engaging plate or plates. The lift cylinders are extended to engage the plate or plates with the ground to lift the rear frame relative to the front frame while simultaneously maintaining the front frame in contact with the ground. Upon alternate extension and retraction of the steering cylinders, the rear frame pivots (slues) relative to the front frame to place the work implement into an infinite number of work positions.
Swedish patent No. 7700902-5 shows a vehicle having two pivotally mounted wheels adjacent one end of the vehicle which are operated to be raised and lowered by a pair of hydraulic cylinders. The two hydraulic cylinders are operated jointly by a hydraulic valve having raise and lower positions and an intermediate neutral position. When the valve is in neutral a hydraulic connection between the head ends of the two cylinders and another hydraulic connection between the rod ends of the two cylinders permit hydraulic fluid to circulate between the two cylinders to allow the pivotally mounted wheels to adjust to different heights to accommodate the wheels and vehicle to uneven terrain.
In addition to the foregoing patented prior art there is unpatented prior art which is discussed in detail hereinafter.